Close ibook without going to sleep?

It it possible to close the display of an ibook without having it going to sleep, turning off the internet(AIM). Is there a pref. setting that im not looking hard enough for or is there a program or something?

I'll tell you...
There is an app called "KisMac" and it is used for wardriving. Download that, and in the preferences there is an option called "Keep computer awake when running KisMac." Read the warnings though...

There is a program called "screen spanning doctor" used to be available at versiontracker.com but can be found here http://www.rutemoeller.com/mp/ibook/ibook_e.html it allows you to do true dual display as well as not sleep when shut, it does say that it will cause a heat build up, but if you want to do it, it is your machine.